What's the Difference Between a Grand Jury and a Trial Jury?

Put differently, a grand jury hands down an indictment at the beginning of a criminal case. A trial jury decides guilt or innocence at the end of the trial.

Not every case goes before a grand jury, and grand juries are typically used in criminal cases, particularly when felony charges are at stake. A trial jury is common for both criminal and civil cases. A grand jury is private, whereas a jury trial, known as a petit jury, is generally open to the public.

Read on to learn more about the difference between a grand jury and a trial jury.

What Is a Grand Jury?

Many people wonder what a grand jury does. A grand jury helps the prosecutor decide whether to file criminal charges against a suspect. While the grand jury system may vary by jurisdiction, it is most often used in federal and state felony cases. Federal grand juries typically consist of 16 to 23 people. Grand jury members may have jury duty for months at a time.

Sometimes, the district attorney will choose to proceed with a preliminary hearing rather than a grand jury. Both determine whether there is enough evidence to indict someone. A grand jury is private. Besides the jurors, only the prosecutor may attend to present evidence to the jurors. The prosecutor decides what the grand jury investigates, the evidence to present, and what documents to subpoena.

A grand jury does not have to be unanimous to issue an indictment. Depending on the jurisdiction, two-thirds or three-quarters of the individual grand jurors must agree.

If a grand jury finds enough evidence and probable cause for a crime, it will return a grand jury indictment. A grand jury indictment is a formal accusation of a crime by a grand jury. The court will schedule an arraignment once the grand jury returns an indictment. An arraignment is the first court appearance where the defendant is formally charged with the crime(s) that the grand jury decided there was probable cause for in their indictment.

Prosecutors use grand jury proceedings as test runs for trials. But if the prosecutor strongly disagrees with a grand jury, they may ignore the decision.

Grand juries will work closely with the prosecutor, who will explain the law to the jurors. The jurors then have the power to view almost any evidence they wish and question anyone they like. Grand jury hearings are relaxed to allow the jurors as much flexibility as possible. Typically, the parties that appear before a grand jury do not have attorneys, and the rules of evidence allow much more evidence than at a criminal trial. Grand jury proceedings are held in strict confidence to encourage witnesses to speak freely and protect the suspect if the grand jury decides not to bring charges.

What Is a Trial Jury?

A trial jury's job is to render a “guilty" or “not guilty" verdict at the end of a formal criminal or civil trial. The right to a jury trial varies depending on the charge and the potential punishment the charge carries. Smaller than a grand jury, a trial jury usually consists of six to 12 people. If it's a federal case, the trial will take place in a United States District Court. The individual jurors will have jury service for the full length of the trial, which could last a few days, several weeks, or even months.

Trial court procedure is extremely strict and controlled entirely by the judge. In a criminal court, the jury must unanimously decide on the verdict. Unlike a grand jury, a trial jury usually has no say in what evidence they get to see. Each party's attorney carefully chooses evidence in trials and must adhere to rules to ensure the evidence is reliable. Trial juries rarely have the opportunity to ask questions. Some jurisdictions may allow jurors to ask direct questions, but in most cases, the jury must submit questions to the judge, who will then determine whether to answer them. Normally these questions arise when the jury wants to clarify some things during deliberations. In contrast to a grand jury, criminal law requires trial juries to find proof beyond a reasonable doubt to return a guilty verdict.

More Questions About the Difference Between a Grand Jury and a Trial Jury? Ask a Lawyer

If you're being investigated for a crime or if you've been charged and may soon face a jury, it's in your best interests to reach out to the law office of a criminal defense lawyer for legal counsel. An experienced criminal defense lawyer knows the ins and outs of the criminal justice system and criminal procedure. Contact a criminal defense attorney near you for legal advice.